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The Great Australian Barrier Reef extends over hundreds of thousands of square kilometers, encompassing a vibrant ecosystem of brightly colored corals and a vast basin of marine life.
However, a recent study found that 30% of its corals died during a nine-month heat wave from March to November 2016.
This discovery highlights the continuing threat to coral reefs in the world. In the last 30 years alone, more than 50% of the world's coral reefs have died.
Warming waters, pollution and overfishing are just some of the many factors that affect these unique ecosystems.
Fortunately, many researchers, ecologists and activists around the world have tapped into their resources to help conserve and restore these vital structures.
The Importance of Coral Reefs
Coral reefs cover less than 1% of the seabed, but they have long been regarded as one of the most valuable ecosystems on the planet.
unit than any other existing marine environment, including a quarter of the world's fish, and 30 percent of total marine biodiversity. Species such as corals, clams, lobsters, seahorses, sponges and sea turtles are just some of the many creatures that depend on coral reefs to survive.
But marine species are not the only ones to depend on coral reefs for their livelihood.
About 500 million people around the world rely on coral reefs for food and income, with 30 million people almost totally dependent on reefs, according to the US National Oceanic and Atmospheric Administration .
Coral reefs provide income to coastal communities through fishing, recreation and tourism, and are an important source of food and coastal protection for millions of people each year.
In addition, coral reefs bring billions of dollars every year to the world's economies.
It is therefore not surprising that their continued degradation has a significant ecological, economic and cultural impact on people and places around the world.
"The livelihoods of many people are highly dependent on fisheries, tourism, and coastal protection, all of which are provided by healthy coral reefs," said Aric Bickel Project Leader and Director. Workshop at SECORE International [19659003] a leading organization for the protection and restoration of coral reefs. "If we want to conserve the important ecological and economic services provided by coral reefs, we must protect and restore the reefs."
Unfortunately, coral reefs face persistent threats and losses.
degradation, 90 percent of all coral reefs will be highly endangered by 2030.
What kills coral reefs?
Increasingly, coral reefs are subject to the stress of rising sea temperatures, pollution, invasive fishing, careless tourism and natural phenomena.
However, according to NOAA, the top three threats to coral reefs – climate change, unsustainable fishing and pollution from land-based sources – are all due to human activity.
Of these three, perhaps the greatest threat to coral reefs comes from rising sea temperatures
Although coral reefs can provide food, shelter and other resources to Thousands of creatures, they sensitive structures, especially when it is heat.
For a reef system to form, coral larvae attach themselves to coastal rocks or soil first. The larva then develops into coral polyps, or tiny animals that excrete calcium carbonate to build an exoskeleton.
Meanwhile, coral polyps develop a symbiotic relationship with algae, which helps them grow. As they grow, they excrete more calcium carbonate, which allows more and more coral polyps to attach to the surface, and eventually, a coral reef is formed.
But, when the water near a reef is overheated, the coral alga begins to produce toxins and corals expel them from their tissue in self-defense. Known as Coral Bleaching this process turns corals into a ghostly white, leaving them stressed and vulnerable to starvation or disease.
"If corals are stressed, one of the first things that happens is that they stop breeding.They simply do not have the energy to produce all these gametes , eggs and sperm, because they're trying to survive, "said Mr. Bickel.
But a whitening event does not necessarily mean that a coral reef will die. 39 water drops quite rapidly, corals can be healed by growing new seaweed
Unfortunately, for many reefs, this opportunity never happens.
Because of the increasingly hot oceans, coral bleaching has become five times more common in the world than it was only 40 years ago.
Effects of Climate Change
Overall, l & # 39; The ocean has warmed to about 1.6 degrees Fahrenheit during last 100 years, according to NOAA.
Moreover, from 2014 to 2017, the increase in sea temperature due to an El Niño climatic event gave rise to the longest, most widespread bleaching event and the most damaging to date.
The event was so bad that in 2016, scientists reported that 93% of the Great Barrier Reef was laundered.
Since then, mass launderings have been documented in the Pacific Ocean, the Indian Ocean, the Caribbean and Australia. Hawaii and Florida Keys – a reality that has serious implications for the planet.
In addition to causing damage to the many species that depend on reefs to feed and shelter, coral bleaching can result in stunted reef growth, a problem that will have serious repercussions on the reefs. coastal communities.
According to a new study conducted by the Exeter University in the United Kingdom, bleaching of the Caribbean and Indian Ocean oceans has affected growth rates corals to the point where soon many reefs will be unable to with rising sea levels.
Among other reasons, this is problematic for coastal communities as coral reefs often provide a natural barrier against the sea. Erosion and floods.
"Average vertical reef growth rates in the Indian Ocean and Caribbean regions are currently about 2 mm per year, but sea level rise projections, even very modest, are around 6 mm per year " ] Professor of Physical Geography at Exeter University
" As a result, there is an increasing divergence between the two and this will begin to reduce the ability of reefs to limit exposure to coastal waves – with increasingly obvious threats to coastal communities from shoreline erosion and flooding, "he continued.
unless urgent measures to reduce CO2 emissions are undertaken by 2100, Perry fears that reef flooding is a serious threat to coastal communities.
"Essentially, what is needed , it's a combination of actions glo bales (policies) on CO2 emissions – this is important because it contributes to warming that can affect the reefs via bleaching events and because it increases the sea level. problem, and we need to see local actions to protect the reefs and reduce the effects of local stressors such as poor water quality (from wastewater, etc.), "he said.
What can be done to save the corals?
With the severity of coral reef degradation at the head of many scientists, many approaches to coral restoration have been adopted.
Large-scale Restoration Approach
A method that has gained popularity in recent years is the sexual reproduction capabilities of coral reefs .
In collaboration with a network of international researchers, SECORE has developed a sexual restoration approach " sowing " that could be used for large-scale efforts.
The idea behind this approach is to collect massive amounts of coral larvae during a spawning period and attach them to specially designed tetrapod substrates that can get stuck between the crevices of the reefs.
Once the larvae have been transformed into initial coral polyps, researchers can deposit the substrates of the boats on degraded reefs, as farmers scatter seedlings on a field.
"By designing substrates (we call them seedling units) that self-colonize and can be sown from a boat or by other methods (similar to how a farmer sows seeds), we can eliminate much of the human labor needed and dramatically reduce the final cost of each transplanted coral, "said Bickel.
Compared To the manual restoration efforts undertaken by divers, which require several hundred to a few thousand person-hours, this method can be performed in less than 50 man-hours, making it 90% more efficient to restore the reefs.
"If we want restoration to play a more significant role in the conservation of coral reefs, we need to think of new directions," said Bickel. "Our approach to sowing is an important step towards improving the quality of our coral reefs. reached this goal since it will make it possible to treat a large number of corals in a very short time at much lower costs. "
In addition, this sowing process allows researchers to promote genetics. He explained that diversity is essential to prepare future reefs for the increase of sea temperature.
Up to now, research has been tested on reefs in Curacao, Mexico, in the Bahamas, Guam, the US Virgin Islands and the Philippines.
SECORE has partnered with California Academy of Sciences and Nature Conservancy to pursue its production goals of one million corals by 2021, in the framework of Although Bickel explained that the approach of sowing could be initiated on a global scale, he stressed that there was no quick fix for the restoration of coral reefs. .
In other words, all the reefs are different, so not all reefs will require the same restoration methods – some might require a mix of restoration approaches, while d & # 39; Others could not.
Building on this idea, researchers at the University of California at Santa Barbara have advocated the integration of unique natural processes and ecological forces to drive the efforts restoration.
Inspired by an expert meeting of Caribbean restoration led by the Florida Fish and Wildlife Conservation Commission researchers outlined a scientific framework to improve restoration in based on decades. research on the ecology of coral reefs.
They finally proposed that scientists examine the ecological qualities specific to the context of the reefs with which they work in order to carry out effective and appropriate restoration practices. "Recognizing that ecological processes play an important but little-known role in coral restoration, the framework we propose is a combination of inputs, survey results, and lessons learned from these practitioners. 39, other practitioners of coral restoration. " a doctoral student at UC Santa Barbara, who led the research.
Researchers have determined that restoration practitioners can control factors such as the density, diversity, and identity of transplanted corals.
"It is essential that we understand the important processes that shape coral reef communities to be able to effectively incorporate and promote positive processes – or reduce negative processes – to make coral restoration more effective." said Ladd.
This research solidifies the importance of understanding the functions and practices of each unique coral ecosystem before initiating a restoration effort.
Local Approach
Many research teams have also undertaken smaller, more localized efforts to help coral reefs.
For example, a recent report by Duke University showed that local efforts, such as the protection of coral reefs from predators, can significantly improve the resilience of corals to bleaching.
In this study, researchers focused their efforts on brain corals found in the Florida Keys, which are known to be highly susceptible to snail predation.
In 2014, during a three-month oceanic temperature spike, researchers descended to the Keys and physically removed snails from some waterfowl sites. brain corals. Their idea was to see if the elimination of predators could help the corals withstand the warmer temperatures and, therefore, decrease bleaching.
And it worked.
When the researchers returned to the reefs after the water temperatures had cooled, they found that corals with fewer snails experienced only 50% bleaching, while corals High-density snails were almost 100% bleaching.
"Our results suggest that local conservation efforts can play an important role in coral reef conservation in addition to large-scale global efforts to mitigate or halt climate change, "says Elizabeth Shaver PhD student in 2018 from the Nicholas School of Environmental Duke, who is now a coral restoration researcher at The Nature's Reef Resilience Program Conservancy
several other interventions that can be initiated at the local level to help protect coral reefs from warm temperatures.
"Nutrient pollution and overfishing of herbivorous parrotfish are common local threats for coral reefs, and both of these threats can increase coral bleaching during hot weather. We need to test whether the elimination of these threats can also help the corals to be more resilient. "
The researchers are reopening the discussion on launching localized efforts at a time when more and more people are saying that local actions are not enough – a difference, and that more Money should be put into global efforts.
"Our research highlights the need for further experiments to test other local management actions that can help corals to be more resilient to disease." climate change and save time as climate change can be long and difficult. Shaver says.
Conclusion
"It is urgent to develop effective strategies to restore the valuable corals and services that they provide," said Dr. Ladd.
Fortunately, researchers at SECORE predict that coral restoration efforts will likely become as frequent as reforestation and help change the future reef landscape as best as they can.
However, Bickel adds that restoration alone will not solve The Coral Reef Crisis
Researchers around the world believe that coral reefs will not last long if global efforts are not made to combat climate change.
Until then, restoration is our best hope.
"Restoration of these services should be our priority," said Bickel. "Nevertheless, coral restoration can only save us time. Time we must use to solve the greatest challenge of our time – global climate change. "
